Recording apparatus



Sept. 11, 1962 A. P. LANG 3,053,540

RECORDING APPARATUS Original Filed Feb. 4, 1954 5 Sheets-Sheet 1INVENTOR.

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RECORDING APPARATUS I Original Filed Feb. 4, 1954 5 Sheets-Sheet 3INVENTOR A TTOR YS A. P. LANG RECORDING APPARATUS Sept. 11, 1962 5Sheets-Sheet 4 Original Filed Feb. 4, 1954 m whw INVENTOR. z4fberz Langp 1962 A. P. LANG 3,053,540

RECORDING APPARATUS Original Filed Feb. 4, 1954 5 Sheets-Sheet 5 v fberzPic/n9 BY A TTOR E YS United States Patent ()fiiice 3,053,540 PatentedSept. 11, 1962 3,053,540 RECGRDING APPARATUS Albert P. Lang,Philadelphia, Pa., assignor to Armour Research Foundation of IliinoisInstitute of Technology, Chicago, Ill., a corporation of IllinoisOriginal application Feb. 4, 1954, Ser. No. 408,197, new Patent No.2,925,281, dated Feb. 16, 1960. Divided and this application Dec. 21,1959, Ser. No. 861,008 Claims. (Cl. 274-4) This invention relates tomagnetic recording and generally has to do with magnetic recordingapparatus of the kind in which magnetic sheet records are scanned whilewrapped around a revolvable support.

Such apparatus is well suited for ofiice dictation purposes; and theinvention is here illustrated and described as embodied in an improvedofiice dictation machine.

The machine in question is of the general kind disclosed in US. Patentto Bruce Roberts No. 2,653,819 and in application Serial No. 11,993filed February 28, 1948, now U.S. Patent No. 2,745,904, both of whichare assigned to the assignee of the present application. The presentapplication is a division of my copending application Serial No. 408,197filed February 4, 1954, now US. Patent No. 2,925,281 issued February 16,1960.

Dictating machines of the kind disclosed in the above mentioned patentand application include a rotatable mandrel for supporting a removablerecord sheet, a carriage movable axially of the mandrel,recording-reproducing and erasing means mounted on the carriage andadapted to scan a track on a record carried by the record support,mechanism for rotating the support, mechanism for propelling thecarriage both in a normal scanning sense and in a back-spacing sense, anamplifier, an external trans ducer or transducers and controls for thescanning mechanism and for the amplifier.

It is a general object of the present invention to improve and simplifythe control and operating characteristics of office dictating machines.

Another object of the invention is to provide machines of the characterdescribed with improved facility for sheet record loading and unloading.

A further object of the invention is to provide for simplified loading,mounting, and stripping of a record sheet.

Still further the invention contemplates improvements in the drivemechanism of the machine and in the control thereof.

The invention also contemplates an improved and simplified system forcontrolling back spacing and condition switching.

How the foregoing and other objects of the invention are attained willbe understood more clearly upon reference to the description whichfollows and from the drawings, in which- FIGURE 1 is a plan view of thedictating machine of the invention;

FIGURE 2 is an end View of the machine of FIGURE 1 looking toward theright;

FIGURE 3 is a sectional view on the line 33 of FIG- URE 1;

FIGURE 4 is a fragmentary sectional view, on a reduced scale, taken onthe line 44 of FIGURE 1;

FIGURE 5 is a front elevational view of the machine partly in section onthe line 5--5 of FIGURE 2;

FIGURE 6 is a sectional elevation on the line 6-6 of FIGURE 3; and

FIGURE 7 is a fragmentary cross section on the line 77 of FIGURE 1.

It will be understood that the machine is illustrated with the coverremoved.

The major parts of the machine are supported by-or between a pair of endplates 10 and 11, which are flanged at the bottom as at 1213 of FIGURE 6and secured to the bottom plate 14 as shown in FIGURE 2.

Turning now to FIGURE 1, a cylindrical record carrier generallyindicated at 15 is mounted on a shaft 16, which shaft is journalled inbearings 17 and 18, which are secured to end plates 10 and 11 bybrackets 19 and 20 respectively. Shaft 16 also carries a driven wheel 21which is provided with a tire of rubber or similar material 22.

As may best be seen in FIGURE 2, the carrier 15 is driven by a motor 23provided with a mounting 24, which mounting is secured to end plate 10by shock mountings generally indicated at 25. Motor shaft 27 extendsthrough end plate 10, where it is engaged by a shiftable intermediaterubber-tired drive element or puck 28. Puck 28 is secured by a pin 29 tomovable link 30, the other end of which is pivotally secured by a pin 31to a crank generally indicated at 32, which is pivotally secured by apin 33 to end plate 10. The lower arm 34 of crank 34 is biased towardthe front of the machine by a spring 35, which interconnects arm 34 witha bracket 36 secured to end plate 10. It will be seen therefore, thatthe spring 35 tends to draw link toward the rear, carrying with it puck28, until the shouldered portion 3 8 of puck 28 engages tire 22 ofdriven wheel 21.

However, rearward motion of link 30 is stopped short of engagementbetween shoulder 38 and wheel 21 by an adjustable stop screw 39 threadedin a nut 40, carried by arm 41 of a second crank generally indicated at42. The lower arm 43 of crank 42 is biased toward the rear of themachine by a spring 44 with the result that stop screw 39 opposesrearward movement of link 30 and holds drive puck 28 out of engagementwith driven wheel 21, so long as crank 42 is in its maximum clockwiseposition responsive to the action of biasing spring 44.

Crank 42 is adapted to be oscillated in the counterclockwise directionby solenoid 45 having an armature 46 connected to arm 43 of crank 42 bya link 47. Armature 46 is provided with a fibre washer 48 which servesto limit movement of armature 46 into solenoid 45 on energizationthereof and to thereby limit counter-clockwise movement of crank 42.

Stop 48 is so located that stop screw 39 is entirely clear of the upperarm of crank 32 when the solenoid is energized and shoulder 38 of puck28 is fully engaged with driven wheel 21 responsive to the bias imposedby spring of crank 32.

It will be seen, therefore, that record carrier 15 may be selectivelystarted and stopped by energizing and deenergizing solenoid 45. Theenergization of solenoid is controlled by a start-stop switch, notshown, which may conveniently be located on the hand microphone used bya dictating operator or on a foot switch used either by a dictatingoperator or a transcribing operator.

Lead screw 49 is rotatably supported between end plates 10 and 11 by anadjustable mounting 50 at the right hand end and a spring held mounting51 at the left hand end to provide for slight adjustment of the axialposition of lead screw 49 relative to record carrier 15. Lead screw 49is driven by a chain 52 which engages a sprocket 53 on record carriershaft 16 and a sprocket 54 secured to lead screw 49. Accordingly, thelead screw 49 rotates whenever the drive to record support 15 isestablished.

A rod 55 extending between end plates 10 and 11 parallel to the axes ofcarrier 15 and lead screw 49 provides a carriage way for a carriagegenerally indicated at 56. Carriage 56 comprises an upper portion 57 onwhich are journalled two opposed pairs of rollers 58. Rollers 58 aregrooved and engage opposite sides of rod 55 and provide for freetraversing movement of the carriage 56 along rod 55 and also permitoscillation of the upper portion 57 of the carriage about the axis ofrod 55. Mounted on upper portion 57 of the carriage 56 is an arm 59 towhich is pivotally secured an equalizer 60 carrying at its forward endan erasing head 61 and at its rearward end a recording-reproducing head62. Equalizer 60 is pivotally mounted on arm 59 by a pivot pin 63 and isbiased in the counter-clockwise direction by a spring 64, oscillation inthat direction responsive to the bias of spring 64 being limited byengagement of an abutment 65 formed on equalizer 60 against a flange 66formed on arm 59. Since the entire head assembly is well forward on rod55, the point about which upper carriage member 57 oscillates, the headassembly is urged toward record carrier 15 by gravity. As will be seenfrom FIGURE 3, if the head assembly is allowed to fall toward thecarriage, recording-reproducing head 62 will first engage a record onthe support and the weight of the carriage assembly will then causeequalizer 60 to oscillate about pin 63 against the bias of spring 64until erasing head 61 also engages a record on the carriage.

Upper carriage part 57 also carries a half nut 67, the

nut 67 being secured to carriage member 57 by a spring metal strip 68 ina position such that it engages lead screw 49 when the heads engage arecord on the carrier but clears the threads of lead screw 49 when theheads are retracted as shown in FIGURE 3.

The upper carriage member 57 is also provided with a foot 69 whichextends forwardly and downwardly and which cooperates with a tilt bar 70to provide for oscillation of upper carriage member 57 about the axis ofrod 55. Tilt bar 70 is mounted on a rod 71, which in turn is journalledin end plates 18 and 11, and is so disposed relative to foot 69 thatwhen it is oscillated in a counterclockwise sense, it engages foot 69and urges upper carriage member 57 in a counter-clockwise sense. Statedotherwise, when tilt bar 70 has been oscillated to its upper position,it prevents heads 61 and 62 from engaging a record on the carrier andprevents inter-engagement between nut 67 and lead screw 49 responsive tothe gravity bias above mentioned. However, when tilt bar 70 is tilted toits lower position, the heads are free to engage the record and the nutis free to engage the lead screw.

Tilt bar 70 is controlled by the linkage already dis cussed inconnection with the drive control mechanism illustrated in FIGURE 2.Thus, it will be seen that tilt bar 70 is connected by a link 72 to arm73 of crank 42. It will also be noted that link 72 is made in two parts,an upper part 74 and a lower part 75, the two being adjustably connectedby a screw-and-slot arrangement generally indicated at 76. A crank arm77 is adjustably secured to rod 71 by a bushing 80 and set screw 26.Crank 77 carries a brake shoe 78 positioned inside driven wheel 21 andis adapted to engage an inner surface of the flange 79 of wheel 21 whenarm 77 is rocked in a counter-clockwise direction. It should also benoted at this time that the engagement between brake shoe 78 and flange79 establishes the counter'clockwise limit of movement of rod 71 andtilt bar 70 and also establishes a limit for the entire systemcomprising link 72, crank 42, link 47 and solenoid armature 46.

Thus, according to the invention, when the solenoid is not energized,spring 44 pulls lower arm 43 of crank 42 to the rear, thus causingupward movement of crank arm 43, link 72, crank arm 77 and brake shoe78. This movement is limited by engagement of brake shoe 78 with flange79 of wheel 21. As a consequence, the full force of spring 44 isavailable to energize the brake.

The position of tilt bar 70 relative to rod 71 is such that in thisposition of rod 71 (the position rod 71 occupies when the brake is fullyengaged), upper carriage portion 57 is oscillated counter-clockwise by adistance sufficient to raise heads 61 and 62 clear of the record and toraise nut 67 clear of lead screw 49.

It should also be noted that in this same position (i.e., with brakeshoe 78 fully engaged) stop screw 39 on arm 41 of crank 42 is carriedfar enough in a clockwise direction to prevent engagement between theshoulder portion 38 of intermediate wheel 28 and driven wheel 21.

When solenoid 45 is energized, on the other hand, armature 48 moves tothe right as viewed in FIGURE 2 until stop 48 strikes the solenoidhousing. In this position, stop screw 39 has shifted counter-clockwisesufficiently far to permit engagement between shoulder 38 ofintermediate wheel 28 with driven wheel 21; brake shoe 78 has movedsufliciently far in a clockwise sense to clear flange 79; and tilt bar70 has moved Sufliciently far in a clockwise sense to clear foot 69 ofcarriage member 57, even though heads 61 and 62 are fully engaged with arecord on the carrier and half nut 67 is fully engaged with lead screw49.

It will thus be seen that in the condition just described, i.e., withsolenoid 45 energized, stop 39 has been rendered ineffective so that theintermediate drive wheel is brought into engagement by its bias spring35 and the tilt bar has been made ineffective to prevent engagement ofthe heads with a record and the nut with a lead screw responsive to thegravity bias on upper carriage member 57. On the other hand, thesolenoid has overcome the bias provided by the spring 44 which wouldotherwise cause engagement of brake 78 with flange 79 of driven wheel21.

It will be noted that as a consequence of this arrangement, theengagement of each element can be adjusted separately without effectingthe adjustment of the others. Thus, engagement of intermediate wheel 28is independently adjustable by means of stop screw 39. The relativepositions of brake shoe 78 and tilt bar 70 can be adjusted by means of aset screw 26 on bushing 80 which secures crank 77 to rod 71. Engagementof tilt bar 70 can be adjusted by means of screw-and-slot arrangement76.

The apparatus also includes mechanism for driving the carriage in a backspacing or reverse direction, i.e., from right to left as viewed inFIGURES 1, 5 and 6. Carriage 56 includes a lower member 81 which issecured to carriage member 57 by means of bushings 82, whose innerdiameter is somewhat in excess of the outside diameter of rod 55. Whilethis member 81 travels back and forth across the machine with carriagemember 57, it is constrained against oscillation about rod 55 by a strap83 which in turn is connected to a channeled member 84 which passesunder and around carrier 15 to the front of the machine, where itsupports a pointer 85, which cooperates with a scale 86 to indicate theposition of the carriage axially of the record support. Oscillation ofcarriage member 81 in the clockwise direction is prevented byinterengagement between channeled member 84 and a member 87 which alsoserves to support scale 86. Counter-clockwise rotation is prevented byinter-engagement between the pointer and flange 88 developed on thebottom edge of the central portion of stripper plate 89.

Carriage member 81 also carries with it a pawl 90 formed from a strip ofspring material and secured to member 81 by bolt 91. Pawl 90 ispositioned to be engaged by a rack 92 having on its upper surface astrip of rubber or similar material 93. As may best be seen in FIGURE 6,rack 92 is provided with a cam surface 94 at its left hand end and a camsurface 95 at its right hand end, which surfaces rest in apertures inwear plates 96 and 97 respectively, which are secured to end plates 10and 11. A web 98, which is secured to rack 92, is interconnected withthe armature 99 of back space solenoid 100 by a link 101. It will beseen that upon energizration of solenoid 100 rack 92 will be drawn tothe left as seen in FIGURE 6, as a consequence of which it will slide upon cam surfaces 94 and 95 into engagement with pawl 90; and, that, as itcontinues in its leftward movement, it will propel carriage 56 to theleft for a short distance. Upon de-energization of solenoid 100, rack 92will be restored to its rightward position by a spring 102 (see FIGURE3). This spring extends at an angle of about 45 downwardly and to theright from the portion of rack 92 broken out in FIGURE 6 to a hole 37 inend plate 11 as shown in FIGURE 3.

The apparatus also includes electronic circuits including an amplifierand other elements used during recording and reproducing and which areenclosed in an electronic chassis generally indicated at 103. Among theelements included in chassis 103 are recording and reproducing volumecontrols 104 and 105, and a condition switch generally indicated at 106,which switch is adapted in one position to condition the apparatus forreproducing and in the other position to condition the apparatus forrecording. Shaft 107 of switch 106 is adapted to be oscillated by acrank 108 to which is connected by means of a pin 109 a link 110carrying a Dictate push button 111. The switch is urged toward reproduceposition by a spring 112 but is adapted to be maintained in Dictateposition by a latch mechanism generally indicated at 113 and including alink 1114 and a vertical plate 115 having therein a vertical slot 116through which the end of link 114 extends. A notch 117 in the lowersurface of link 114 permits link 114 to drop when button 111 is pushedto the rear. When link 114 has dropped, interlocking between notch 117and vertical plate 115 prevents forward motion of link 114 responsive tothe bias of spring 112, thus holding switch 106 in the record or Dictateposition. The latch 113 is released by a crank 118 having horizontal arm119, which extends under 'link 114. Crank 118 is pivotally secured tovertical plate 115 by a pivot pin 120. It will be seen that acounter-clockwise torque applied to upper arm 121 of crank 118 willraise link 114 until the notch 117 clears plate 115, whereupon spring112 will throw the switch 106 to the reproduce position and restorebutton 111 to its extended position. Such a torque. is adapted to beapplied to vertical arm 121 by a link 122 interconnecting arm 121 withthe armature 99 of the back space solenoid 100. A small spring 123restores crank 118 to inoperative position when the torque applied bysolenoid 100 is removed.

From the foregoing description it will be seen that energization of backspace solenoid 100 will not only cause back spacing of the carriage, butwill also (assuming that the apparatus is in dictating condition) causethe apparatus to be switched to reproducing condition. Thus, it isimpossible to back space the carriage while the apparatus is indictating condition and inadvertently erase the material in advance ofthe new position of the carriage, although it is possible to erase suchmaterial deliberately merely by depressing button 111 to again switchthe apparatus to recording condition.

The apparatus of this invention also includes the direction sensitiveswitch disclosed in eo-pending application Serial No. 11,993, filedFebruary 28, 1948, assigned to the assignee of the present invention.This switch, which may be seen at 124 in FIGURE 5 is actuated by a rod126, which in turn is adapted to be driven by a fibrous bushing 127carried by a double arm 128, which is driven by arm 59 of carriage 56.The switch is so arranged that upon any movement of the carriage in aback spacing direction whether effected manually or by the mechanismabove described, the switch 124 closes, energizing solenoid 100 with theresult that the apparatus is shifted to reproduce condition as abovedescribed.

A second switchnot shownis mounted in the electronic chassis 103 and hasan oscillatable operating member 129 (see FIGURE 3). This second switchis connected electrically in parallel with switch 124 and is biased toopen position by a spring 130 which spring is connected at one end tomember 129 and at the other to a post 131. Operating member 129 isadapted to be actuated to the closed position of the associated switchagainst the bias of spring 130 by a link 132 carrying at its forward enda Listen button 133. It will be seen,

6 therefore, that each time button 133 is depressed, the carriage willbe back spaced a distance determined by the geometry of the back spacingmechanism, and that in addition, if the apparatus is in recordingcondition, de pressing button 133 will result in the actuation of switch106 to reproduce condition.

The portions of the apparatus so far described provide for control ofthe drive to the record support and to the carriage, for control of backspace, and for control of the electronic components of the machine toprovide for switching from record to reproduce condition. Features ofthe apparatus having to do with the loading, mounting, and unloading ofrecords are now to be discussed.

The machine of the invention is adapted to be used with rectangularrecord sheets carrying magnetiz-able particles as disclosed in theRoberts patent above mentioned. In particular, the machine employsrecording sheets having a pair of apertures in adjacent corners which,in cooperation with a pair of pins 134, are adapted to establish andmaintain the position of the leading edge of the sheet on record carrier15. In machines of this kind, only the leading edge is secured to therecord support, the trailing edge being wrapped around the support andpreferably overlapping the leading edge by a short distance. The cornersof the trailing edge are cut out to clear the pins 134.

To load the sheet into the machine, a record sheet with its coatedsurface upward and with the edge having the apertures leading, is placedon the upper portion of stripper plate 89 (see FIGURE 3), and slidupwardly along the stripper plate, until the leading edge touches thesurface of the record carrier 15 between flange 135 at the right handend and fingers 136 at the left end. The record support is now rotatedmanually by a knob (not shown) on shaft 16 until pins 134 enter theapertures in the sheet at which time the sheet may be released by thehand and rotation of record support continued either manually or by thedrive motor 23 upon energization of solenoid 45 to wrap the sheet aroundthe carrier 15.

As the support is rotated, the sheet advances into the nip between fixedvguide members 137 and the record carrier surface, and also into the nipbetween that surface and traversing guide 138, which is mounted oncarriage 56. Fixed guides 137, which are adjacent the ends of the recordcarrier 15, conduct the leading edge of the sheet and the followingportions into conformity with the surface of carrier 15. As the rotationcontinues the finger following the pin 134 and shown in FIGURE 3 as13602 engages the underside of the left hand edge of the sheet, holdingthe sheet in that region somewhat away from the surface of the carrier15. However, as this position of engagement moves into the area whereinfixed guide 137 is closer to the surface of carrier 15, the edge of thesheet is forced down along the angled surface 139 of finger 136a,setting up :a compression force in the sheet. Responsive to that force,the sheet shifts to the right as seen in FIGURE 5 until the right handedge abuts against flange 135. When rightward movement of the sheet islimited by such engagement, the remaining force is dissipated by urgingthe finger 136a to the left, as viewed in FIGURE 5, it being noted thatthe finger 136 is only secured to carrier 15 toward its lower end, sothat it is free to bend. As the rotation continues each succeedingfinger 136 reacts in the same way, so that when an entire revolution ofthe carrier 15 has been completed, the record sheet is wrapped aroundthe carrier and throughout its circumference is yieldingly held againstflange 135 by the four fingers 136.

The fingers 136 and their application to machines of this kind aredisclosed and claimed in co-pending application of Lloyd J. Bobb, SerialNo. 408,198, filed February 4, 1954, now abandoned.

The record may now be recorded upon, or intelligence thereon may bereproduced, by energizing solenoid 45, thus causing rotation of carrier15 and translational move- 7 meat of carriage 56 with heads 61 and 62 inscanning engagement thereto, so that the heads scan a helical pathrepeatedly crossing from the trailing edge to the leading portion of therecord.

During this process, the fixed guides 137 maintain the traiilng edge infairly close contact with the carrier surface throughout thecircumference of carrier 15, except for the space between the point 137aand the point 137b, which space is necessary to accommodate loading andunloading of the sheet.

Traversing guide 138 also extends along the surface of carrier in theregion engaged by heads 61 and 62. This guide is mounted on channelmember 34 and extends from a little below the center of carrier 15 inthe rear to the loading space in the upper quadrant in front.

To unload the machine, it is necessary only to reversely rotate thecarrier manually as by a knob (not shown) on shaft 16. When, in suchrotation, the trailing edge is released by upper fixed guide element137a, it straightens out slightly due to its inherent stiffness and maybe caught and stripped by stripper plate 89. Stripper 89, as will beseen in FIGURE 3, is mounted on member 87 by means of screws 140 whichare shouldered as at 141 and on which are mounted rubber grommets 142.This arrangement permits stripper plate to be oscillated slightly aboutan axis passing through the two screws 140, so that the stripper edge143 may be depressed and brought into intimate contact with a record oncarrier 15. It will further be noted from FIGURE 1 that the edge 143 ofstripper 89 is arcuate or pointed, i.e., that it is cut back toward thesides so as to engage the trailing edge of a record at its center beforethe trailing edge is engaged by the outer portions of the stripper. Thisarrangement provides for positive stripper action even when the trailingedge conforms very closely to the cylindrical record support and despitethe presence of the guides 137 at the ends of the carrier.

It should here be pointed out that both the fixed guides 137 and thetraversing guide 138 contribute to the simplicity of the unloadingoperation. In the absence of these guides, forward rotation of thecarrier with a record loaded thereon would be perfectly feasible, sincethe outermost of the overlapped edges under that condition is intrailing position. However, when the support 15 is rotated in thereverse direction, the outermost overlapping edge is in leading positionand will catch on other parts of the machine if not kept fairly close tothe surface of carrier 15. The fixed guides 137 perform this functioninsofar as fouling on fixed portions of the machine are concerned, butinasmuch as the scanning heads and carriage assembly-even in theirdisengaged condition-are relatively close to the carrier surface, itwould be possible for the trailing edge to pile up on the carriage orheads when the latter are located in the middle portion, axiallyspeaking, of their translational path. The traversing guide 138 guidesthe outermost overlapped edge past the heads and carriage assemblyduring reverse rotation, only releasing the edge when it reaches theloading and unloading space in the upper front quadrant of carrier 15.

From the foregoing it will be seen that the drive and drive controlmechanism of the invention is simple and easily adjustable; that theback spacing and switching functions are controlled in an improved andsimplified way; and that the mechanism provides for simplified loadingan unloading of records.

I claim:

1. In a dictating machine, a revolvable record support, a motor fordriving the support, an intermediate drive member selectively engageableto drivingly interconnect the motor and the support, said intermediatemember being biased toward engaged position, a scanning head mountedwith freedom for movement toward and away from engagement with a recordon the support and being biased toward engagement, a brake for thesupport, means biasing said brake toward engaged position, a controlmember, linkage interconnecting said brake and said control member, thecontrol member being actuable against said biasing means to disengagethe brake, a first element actuated by said linkage to remove the headfrom engagement with a record responsive to said biasing means andretractable responsive to actuation of said control member to permitsaid head to engage a record responsivve to its bias, and a secondelement connected with said linkage and actuable responsive to saidbiasing means to shift said intermediate drive member to disengagedposition and retractable responsive to actuation of said control memberto permit said intermediate member to shift to engaged positionresponsive to its bias, said intermediate member being biased towardengaged position by means of a spring having one end fixed and theopposite end coupled to said intermediate member, and the control memberbeing coupled to said intermediate drive member for transmitting forceto the intermediate drive member to move the intermediate drive memberto disengaged position against the action of said spring but beingdisconnected from said intermediate member in an actuated position withthe brake disengaged to provide for biasing of the intermediate drivemember toward engaged position by said spring.

2. Magnetic recording-reproducing apparatus of the kind in whichmagnetic sheet records are helically scanned while wrapped around asupport, comprising a revolvable record support, a lead screw extendingparallel to the support, drive means for revolvably driving the supportand the lead screw, a carriage arranged to traverse a path parallel tothe axis of the support and lead screw and having thereon a scanninghead and a drive nut, the carriage being oscillatable between a firstposition in which the head and nut engage a record on the support andthe lead screw respectively and a second position in which the head andnut are disengaged, the carriage being biased toward the first position,a shiftable control member for the support and lead screw drive means,movable between engaged and disengaged positions, and being biasedtoward the former, movable stop means for blocking oscillation of thecarriage to said first position, movable stop means having abuttingengagement with said control member in a first position for blockingshifting of said control member to engaged position and being entirelydisengaged from said control member in a second position to accommodatemovement of the control member to engaged position under the impetus, abrake for the support and lead screw drive movable with said stop meansin a sense to be effective when said stop means is effective, means forbiasing the carriage stop means and brake to effective positions and forbiasing said control member stop means to said first position, asolenoid for shifting said carriage stop means and brake to ineffectivepositions and for shifting said control member stop means to said secondposition, and a manual control for said solenoid.

3. A dictating machine comprising a record support, a scanning headbiased toward a record on the support, a drive member selectivelyengageable to drive the support, and continuously biased toward engagedposition, a brake selectively engageable to stop the support, linkageassociated with said head, said member and said brake, bias meansconnected to said linkage and acting on the same in a sense to shift thehead and drive member to disengaged positions against their respectivebiases and to shift the brake to engaged position, and a control foractuating said linkage in the opposite sense against said biasing meansto permit the head and drive member to shift to their engaged positionsresponsive to their respective biases and to effect disengagement ofsaid brake.

4. A dictating machine comprising a record-reproduce switch, meansbiasing said switch to reproduce position, a

latch for retaining said switch in record position, back spacingmechanism, a solenoid for energizing said mechanism, linkageinterconnecting said mechanism and said latch for releasing the latchupon energization of said solenoid, and a control for energizing saidsolenoid.

5. A dictating machine comprising a record-reproduce switch, backspacing mechanism, a solenoid, and linkage interconnecting said solenoidwith said switch and said mechanism to provide for simultaneousactuation of said mechanism and operation of said switch to itsreproduce position.

References Cited in the file of this patent UNITED STATES PATENTS

